g200kg has released KeroVee, a free Pitch-Correction plug-in that works as a VST effect on Windows. It can pitch-detect and retune to specified scales or MIDI notes. 'Bypass' and 'SubTone' mix are also available.

Features / controls:

Scale Buttons 'C' to 'B' specify the 'Allowed' note.

Speed: Tuning Speed. Maybe robotic if set to '100=MAX'.

TuneTo (If both are enabled the MIDI note gets priority. But scale tuning is effective after notes are offed):